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Long-term toxicity to aquatic invertebrates

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Reference
Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2013-01-23 to 2013-02-21
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP Guideline study, no deficiencies
Qualifier:
according to
Guideline:
OECD Guideline 211 (Daphnia magna Reproduction Test)
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
- Concentrations: 0.500 - 1.00 - 2.00 - 4.00 - 8.00 mg/L
- Sampling method: All concentration levels of the test item and the control were analysed by LC-MS/MS at the start of the exposure intervals on days 0, 9, 14, 19 (0 h) and at the end of the exposure intervals on days 2, 12, 16, 21 (48 or 72 h).
For the analyses of the old media, separate replicates without daphnids and algae were prepared and stored under test conditions until sampling.
- Sample storage conditions before analysis: All original samples were stored at room temperature until sample preparation. Prepared samples were stored at room temperature until analysis.
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution (8.00 mg/L of the test item were weighed out) was freshly prepared with dilution water at the start of the test period and at every water renewal day. Dispersion treatment was agitation.
- Eluate: Dilution water
- Differential loading: 0.500 - 1.00 - 2.00 - 4.00 - 8.00 mg/L
- Controls: 10 replicates of dilution water without test item.
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia magna STRAUS
- Strain/clone: Clone 5
- Justification for species other than prescribed by test guideline: Daphnia magna STRAUS is recommended in the guideline
- Source: Own breeding (Origin: Institut fuer Wasser- Boden- und Lufthygiene)
- Age of parental stock (mean and range, SD): > 14 days
- Feeding during test
- Food type: Mix of Pseudokirchneriella subcapitata and Desmodesmus subspicatus
- Amount: 0.2 mg C/daphnia per day
- Frequency: renewals 3 times per week


ACCLIMATION
- Acclimation period: 2 h in dilution water
- Acclimation conditions (same as test or not): Same as test
- Type and amount of food: During acclimation the daphnids were not fed
- Feeding frequency: None
- Health during acclimation (any mortality observed): Healthy

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES: The parent animals were removed from the culture medium and the juveniles collected over a sieve and flushed into fresh medium
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
21 d
Post exposure observation period:
Not observed
Hardness:
Total Hardness [mg/L] as CaCO3
Nominal
test item
concentration
[mg/L] I F I F I F
Day 0 Day 2 Day 9 Day 12 Day 14 Day 16
2013-01-30 2013-02-01 2013-02-08 2013-02-11 2013-02-13 2013-02-15
8.00 169 171 Not determined due to 100 % adult mortality
4.00 Not determined 174 180 174 167
Control 176 171 178 155 171 174
Test temperature:
Temperature [°C]
Nominal
test item
concentration
[mg/L] I F I F I F
Day 0 Day 2 Day 9 Day 12 Day 14 Day 16
2013-01-30 2013-02-01 2013-02-08 2013-02-11 2013-02-13 2013-02-15
8.00 20.9 20.7 Not determined due to 100 % adult mortality
4.00 Not determined 19.6 20.1 20.4 19.5
Control 20.8 20.7 19.5 19.9 19.2 19.9
pH:
pH-Values
Nominal
test item
concentration
[mg/L] I F I F I F
Day 0 Day 2 Day 9 Day 12 Day 14 Day 16
2013-01-30 2013-02-01 2013-02-08 2013-02-11 2013-02-13 2013-02-15
8.00 8.33 8.09 Not determined due to 100 % adult mortality
4.00 Not determined 8.01 7.73 7.62 7.45
Control 8.53 8.40 8.36 7.59 8.00 8.05
Dissolved oxygen:
Dissolved Oxygen Concentration [mg/L]
Nominal
test item
concentration
[mg/L] I F I F I F
Day 0 Day 2 Day 9 Day 12 Day 14 Day 16
2013-01-30 2013-02-01 2013-02-08 2013-02-11 2013-02-13 2013-02-15
8.00 8.73 8.33 Not determined due to 100 % adult mortality
4.00 Not determined 8.93 8.07 8.76 6.30
Control 8.70 8.52 9.09 7.73 9.09 8.96
Salinity:
Not measured, freshwater
Nominal and measured concentrations:
Please refer to "Any other information on materials and methods"
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed with parafilm
- Material, size, headspace, fill volume: 100 mL glass beaker, filled with 50 mL test solution
- Aeration: No
- Renewal rate of test solution (frequency): 3 x per week
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control and pH-control (replicates): 10


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Elendt M4, according to ELENDT (1990), modified to a total hardness of > 140 mg CaCO3/L.

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 h light : 8 h dark per day
- Light intensity: Max. 20 µE*m-2*s-1


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Adult mortality: daily
- Number of juveniles: daily
- Stillborn juveniles and aborted eggs: daily
- Appearance of first brood
- Intrinsic rate of natural increase: test end
- Growth (total length and dry weight): test end


RANGE-FINDING STUDY
Based on the results of the acute immobilisation test (NOACK Lab-ID: 120425CS/DAI15130) conducted at the test facility, the definitive reproduction test was carried out with 5 concentration levels of the test item in the range of 0.500 to 8.00 mg/L.


Reference substance (positive control):
yes
Remarks:
Potassium dichromate
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
is UVCB means 100% act.ingr
Basis for effect:
reproduction
Details on results:
- Mortality of parent animals:
The test item induced biologically significant adult mortality of 100 % at the concentration level of 8.00 mg/L during the test period of 21 days. In the concentration levels of 0.500 to 4.00 mg/L and in the control, all parental daphnids survived until the end of the test after 21 days.
The EC50 for the adult mortality was calculated to be 5.66 mg/L (95% confidence limits: 4.00 – 8.00 mg/L.
- No. of offspring produced per day per female:
The average number of living juveniles per surviving parental daphnid at the end of the test after 21 days was 86 in the control group. The reproductive output was statistically significant increased in comparison to the control at the concentration level of 4.00 mg/L (One Way Analysis of Variance, DUNNETT’S method, p = 0.05). At the concentration level of 4.00 mg/L, an increased number of broods and an increased number of living juveniles per brood were observed. At the concentration levels of 0.500 to 2.00 mg/L, the reproductive output was comparable to the reproductive output at the control. Due to 100 % adult mortality, no offspring was observed at the concentration level of 8.00 mg/L.
The EC10 for the increase of the reproductive output was calculated by sigmoidal dose-response regression to be 2.35 mg/L (95% confidence limits: 1.63 – 3.37 mg/L). The EC50 was calculated accordingly to be 3.40 mg/L (95 % confidence limits: 2.39 – 3.97 mg/L).
The coefficient of variation of the number of living offspring produced per parent was 6 % in the control. In the test groups the coefficient of variation was in the range of 11 to 13 %.
- Body length and weight of parent animals:
The mean values of the body length of the surviving parental daphnids in the tested concentration levels of 0.500 to 4.00 mg/L were determined to be in the range of 5.10 to 5.68 mm per daphnid, 5.23 mm per daphnid in the control group.
The mean dry body weight was determined to be in the range of 0.87 to 1.25 mg per daphnid in the concentration levels 0.500 to 4.00 mg/L and 1.21 mg per daphnid in the control

- Type and number of morphological / behavioural abnormalities:
please refer to the respective table
- Time to first brood release or time to hatch:
The first brood was released on days 8 and 9 by all parental daphnids of the control and the concentration levels of 0.500 to 4.00 mg/L. At the tested concentration levels of 0.500 to 2.00 mg/L and in the control, 4 broods were produced by the surviving parental daphnids. At the concentration level of 4.00 mg/L, 5 broods were produced by the surviving parental daphnids







Results with reference substance (positive control):
- Results with reference substance valid? yes
- Relevant effect levels: EC50 (24 h) = 1.69 (CI 1.41 - 2.12) mg/L
Reported statistics and error estimates:
The NOEC and the LOEC based on the increase of the reproductive output were deduced directly from the results. Significant deviations were determined in comparison to the control using statistical standard procedures as normality test, equal variance test and analysis of variance (parametric ANOVA, DUNNETT’S method).
Prior to running the parametric ANOVA, a normality test and an equal variance test were performed. P-values of the normality and equal variance tests should be 0.05. Actually, the P-value was < 0.05 and therefore the equal variance test failed for the statistical evaluation of the reproduction rates.
The -value (acceptable probability of incorrectly concluding that there is a difference) was =0.05.
For the determination of significant deviations of the reproduction rates and the intrinsic rates of natural increase, One Way Analysis of Variance, DUNNETT’S method (p = 0.05) was used.
The EC10- and the EC50-value for the increase of the reproductive
output after 21 days and the EC50-value for the reference item were calculated by sigmoidal dose-response regression. The 95 % confidence limits for the EC-values were calculated from the best-fit values, the standard error and the t-distribution with the software GraphPad prism5.
The EC50-value for the adult mortality after 21 days was calculated as the geometric mean of the highest concentration level causing 0 % adult mortality and the lowest concentration level causing 100 % adult mortality, because only 0 and 100 % adult mortality was observed. These concentration levels were used as confidence limits.
The EC100-value for the adult mortality deduced directly from the observation data without calculation.

The coefficients of variation around the mean number of living offspring produced per parent in the control and the test groups were evaluated.

Number of Juveniles in the Control and Test Groups after 21 Days

Nominal

test item

conc.

[mg/L]

No.

of

parents

prod. juv.

Mean no. of Juveniles

per parent

producing juveniles

Comparison

versus

control

Number of living juveniles in replicate no.

Total

no.

CV

Inc.

Stat.

  1

  2

  3

  4

  5

  6

  7

  8

  9

   10

å

N

MV ± SD

[%]

[%]

8.00

--

--

--

--

--

--

--

--

--

--

n.a.

  0

n.a.

n.a.

n.a.

n.a.

4.00

176

133

139

137

158

156

134

132

171

151

1487

10

149 ±

16

11

72

yes

2.00

  96

100

  93

  91

  94

  88

  98

  66

  79

  92

  897

10

90 ±

10

11

  4

no

1.00

  98

  90

  80

  97

  95

  87

104

  98

  67

  93

  909

10

91 ±

11

12

  5

no

0.500

100

  86

  82

  73

  89

  92

  78

  93

111

  99

  903

10

90 ±

11

13

  5

no

Control

  91

  95

  78

  83

  86

  82

  86

  86

  91

  85

  863

10

86 ±

  5

  6

Relative Number of Dead (Stillborn + Aborted Eggs) to Total Number of Juveniles

Nominal

test item

concentration

[mg/L]

Number of juveniles

Percentage of

dead juveniles#)

[%]

Dead

Alive

Total

8.00

n.a.

n.a.

n.a.

n.a.

4.00

36

1487

1523

2

2.00

34

  897

  931

4

1.00

17

  909

  926

2

0.500

14

  903

  917

2

Control

  1

  863

  864

1

First Appearance of Living Juveniles in the Individual Groups

Nominal

test item

concentration

[mg/L]

Day of first appearance of living juveniles

First

Mean

in replicate no.

appearance

number

1

2

3

4

5

6

7

8

9

10

mean day

of broods

8.00

--

--

--

--

--

--

--

--

--

--

n.a.

n.a.

4.00

8

8

8

8

8

9

8

8

8

8

8.1

5

2.00

9

8

8

8

8

8

8

8

8

9

8.2

4

1.00

8

8

8

8

8

8

9

9

9

9

8.4

4

0.500

8

9

9

9

8

9

8

8

8

8

8.4

4

Control

9

8

9

9

8

9

9

8

9

8

8.6

4

Mortality [%] of the Adult Daphnids after 7, 14 and 21 Days of Exposure

                 (n = 10)

Nominal

Test Item Concentration

[mg/L]

Adult Mortality [%]

7 days

14 days

21 days

8.00

1001)

1001)

1001)

4.00

   0

   0

   0

2.00

   0

   0

   0

1.00

   0

   0

   0

0.500

   0

   0

   0

Control

   0

   0

   0

Total Body Length of the Parental Daphnids

Nominal

test item

concentration

[mg/L]

Total length of the parent animals

[mm]

MV

N

Dry weight
[mg]

Replicate no.

1

2

3

4

5

6

7

8

9

10

[mm]

S

MV

8.00

--

--

--

--

--

--

--

--

--

--

n.a.

  0

n.a.

n.a.

4.00

5.50

5.25

5.50

5.50

5.75

5.50

6.00

5.25

5.75

5.75

5.58

10

  8.7

0.87

2.00

5.00

5.00

4.75

5.00

5.00

5.25

5.50

5.00

5.25

5.25

5.10

10

11.1

1.11

1.00

5.25

5.00

5.50

5.00

5.75

5.25

5.00

5.00

4.75

5.25

5.18

10

12.0

1.20

0.500

6.00

5.75

5.50

5.50

5.75

5.50

5.75

5.50

6.00

5.50

5.68

10

12.5

1.25

Control

5.75

5.25

5.25

5.00

5.50

5.00

5.25

5.50

4.75

5.00

5.23

10

12.1

1.21

Validity criteria fulfilled:
yes
Conclusions:
The significant increase of the reproductive output at the concentration level of 4.00 mg/L was the most sensitive effect in this study. At the concentration level of 4.00 mg/L, an increased number of living juveniles, broods and an increased number of living juveniles per brood were observed.
Therefore, the No Observed Effect Concentration (NOEC) after 21 days was assessed at 2.00 mg/L and the Lowest Observed Effect Concentration (LOEC) was assessed at 4.00 mg/L. Based on the nominal concentrations of the active ingredient, the NOEC was 1.22 mg a.i./L and the LOEC was 2.44 mg a.i./L.
The EC10 for the increase of the reproductive output was calculated by sigmoidal dose-response regression to be 2.35 mg/L (95% confidence limits: 1.63 – 3.37 mg/L). The EC50 was calculated accordingly to be 3.40 mg/L (95 % confidence limits: 2.39 – 3.97 mg/L).
Based on the nominal concentrations of the active ingredient, the EC10 for the increase of the reproductive output was 1.43 mg a.i./L (95 % confidence limits: 0.994 – 2.06 mg a.i./L) and the EC50 was 2.07 mg/L (95 % confidence limits: 1.46 – 2.42 mg/L).
The EC50-value for the adult mortality was calculated to be 5.66 mg/L (95% confidence limits: 4.00 – 8.00 mg/L, which corresponds to 3.45 mg a.i./L (95% confidence limits: 2.44 – 4.88 mg a.i./L based on the nominal concentrations of the active ingredient. The EC100-value for the adult mortality was 8.00 mg/L, which corresponds to 4.88 mg a.i./L.

Endpoints assessed Sodium methyl oleyl taurate
Nominal concentration
of the test item
[mg/L] Nominal concentration
of the active ingredient
[mg a.i./L]
EC10 Reproduction
(with 95 % confidence limits) 2.35 (1.63 – 3.37) 1.43 (0.994 – 2.06)
EC50 Reproduction
(with 95 % confidence limits) 3.40 (2.39 – 3.97) 2.07 (1.46 – 2.42)
EC10 Adult Mortality
(with 95 % confidence limits) 4.00 < EC10 Adult Mortality < 8.00 2.44 < EC10 Adult Mortality < 4.88
EC50 Adult Mortality
(with 95 % confidence limits) 5.66 (4.00 – 8.00) 3.45 (2.44 – 4.88)
EC100 Adult Mortality 8.00 4.88
NOECReproduction 2.00 1.22
LOECReproduction 4.00 2.44
Executive summary:

The Daphnia magna Reproduction Test (semi-static, 21 d) of the test item Sodium methyloleyl taurate (batch number: DEB4003485) was conducted according to OECD 211 (2008) from 2013-01-23 to 2013-02-21, with the definitive exposure phase from 2013-01-30 to 2013-02-20, at Dr.U.Noack-Laboratorien, Käthe-Paulus-Str. 1, 31157Sarstedt, Germany.

Test species was Daphnia magna STRAUS (Clone 5). Ten daphnids, individually held, were used per concentration level, and control. At test start the daphnids were 2 to 24 hours old. The study was carried out undersemi-static conditions with renewal of the test solutions three times per week. Aim of the Daphnia Reproduction Test over 21 days was to assess effects on the reproduction capacity and other test item-related effects or parameters such as time of production of first brood, adult mortality, intrinsic rate of natural increase, occurrence of aborted eggs and stillborn juveniles and body length of the parental daphnids.

Nominal concentrations of Sodium methyloleyl taurate were selected as follows: 0.500 - 1.00 - 2.00 - 4.00 - 8.00 mg/L. This corresponds to the nominal concentrations of the active ingredient of 0.305 – 0.610 – 1.22 – 2.44 – 4.88 mg a.i./L based on the nominal content of 61.0 % (w/w).

The concentrations of the test item Sodium methyl oleyl taurate were analytically verified by LC-MS/MS of samples taken at the start of the exposure intervals on days 0, 9, 14, 19 (0 h) and at the end of the exposure intervals on days 2, 12, 16, 21 (48 or 72 h) of all concentration levels and the control.

The measured concentrations of the test item at the start of the exposure intervals were in the range of 94 to 114 % of the nominal values. This indicates the correct preparation of the test concentrations. At the end of the exposure intervals (48 or 72 h), the measured concentrations of the test item were in the range of  LOQM to 109 % of the nominal values.

Adsorption to the glass walls of the test vessels is expected to be negligible. The adsorption was monitored during the acute toxicity test to zebrafish (NoackLab-ID: FAZ15130/120425CS) conducted at the test facility, which results in sorbed amounts of the test item of 1 to 8 % of the nominal values. Due to this fact, it can be assumed, that test item is present in the test solutions. Nevertheless, the test item is available for exposure. Therefore, the nominal concentrations were used for assessment of the endpoints instead of measured ones.

·   The average number of living juveniles per surviving parental daphnid at the end of the test after 21 days was 86 in the control group. The reproductive output was statistically significant increased in comparison to the control at the concentration level of 4.00 mg/L (One Way Analysis of Variance, Dunnett’smethod, p = 0.05). At the concentration level of 4.00 mg/L, an increased number of broods and an increased number of living juveniles per brood were observed. At the concentration levels of 0.500 to 2.00 mg/L, the reproductive output was comparable to the reproductive output at the control. Due to 100 % adult mortality, no offspring was observed at the concentration level of 8.00 mg/L.
The EC10 for the increase of the reproductive output was calculated by sigmoidal dose-response regression to be 2.35 mg/L (95% confidence limits: 1.63 – 3.37 mg/L). The EC50 was calculated accordingly to be 3.40 mg/L (95 % confidence limits: 2.39 – 3.97 mg/L).


·   Based on the significant increase of the reproductive output at the concentration level of 4.00 mg/L, the No Observed Effect Concentration (NOEC) after 21 days was assessed at 2.00 mg/L and the Lowest Observed Effect Concentration (LOEC) was assessed at 4.00 mg/L.

·   The coefficient of variation of the number of living offspring produced per parent was 6 % in the control. In the test groups the coefficient of variation was in the range of 11 to 13 %.

·   No stillborn juveniles and 1 aborted egg were observed in the control group during the exposure period of 21 days. Related to the total number of produced juveniles (dead + alive) the percentage of dead juveniles was in the range of 2 to 4 % in the tested concentration levels of 0.500 to 4.00 mg/L.

·   The intrinsic rates of natural increase (IR) of the surviving parental daphnids accounting for generation time and number of offspring were used for calculation of population growth and maintenance. The intrinsic rates of natural increase determined for the surviving daphnids at the concentration levels of 0.500 to 4.00 mg/L were comparable to the IR at the control (One Way Analysis of Variance, Dunnett’s method, p = 0.05).

·   The first brood was released on days 8 and 9 by all parental daphnids of the control and the concentration levels of 0.500 to 4.00 mg/L. At the tested concentration levels of 0.500 to 2.00 mg/L and in the control, 4 broods were produced by the surviving parental daphnids. At the concentration level of 4.00 mg/L, 5 broods were produced by the surviving parental daphnids

·   The test item induced biologically significant adult mortality of 100 % at the concentration level of 8.00 mg/L during the test period of 21 days.In the concentration levels of 0.500 to 4.00 mg/L and in the control, all parental daphnids survived until the end of the test after 21 days. The EC50for the adult mortality was calculated to be 5.66 mg/L (95% confidence limits: 4.00 – 8.00 mg/L).

·   The mean values of the body length of the surviving parental daphnids in the tested concentration levels of 0.500 to 4.00 mg/L were determined to be in the range of 5.10 to 5.68 mm per daphnid, 5.23 mm per daphnid in the control group.

     The mean dry body weight was determined to be in the range of 0.87 to 1.25 mg per daphnid in the concentration levels 0.500 to 4.00 mg/L and 1.21 mg per daphnid in the control

·       No males or ephippia (winter eggs) were observed in the control or in the test groups.

 

·   Water quality parametersas pH-value, dissolved oxygen, water hardness and temperature were determined to be within the acceptable limits.


IMPORTANT NOTE TO AVOID CONFUSION:

As the registration substance is a UVCB this means that the test item is 100% active ingredient.

A summary of all test item related effects concerning the reproduction and the assessed endpoints based on the nominal concentrations of the test item is given in Table 1.

Table 1:           Test Item Related Effects on the Reproduction (NOEC, LOEC, EC10, EC50and EC100)

                         (based on the nominal concentrations of the test item )

Effects

Sodium methyl oleyl taurate

Nominal concentrations of the test item [mg/L]

Control

0.500

0.305

1.00

0.610

2.00

1.22

4.00

2.44

8.00

4.88

Mean Number of Living Juveniles per

Producing Parent (Reproduction Rate ± SD)

86 ± 5

90 ± 11

91 ± 11

90 ± 10

149 ± 161)

---

Coefficient of Variation of the Mean Number of Juveniles per Producing Parent [%]

  6

13

12

11

  11

---

Mean Number of Broods

  4.00

  4.00

  4.00

  4.00

    5.002)

---

Appearance of First Brood [Mean Day]

  8.6

  8.4

  8.4

  8.2

    8.1

---

Mean Intrinsic Rates of Natural Increase

  0.45

  0.46

  0.46

  0.47

    0.48

---

Percentage of Dead Juveniles Related to the Total Number of Juveniles [%]

1

  2

  2

  4

    2

---

EC10 Reproduction

(with 95 % confidence limits)

2.35 mg/L (1.63 – 3.37 mg/L)

EC50 Reproduction

(with 95 % confidence limits)

3.40 mg/L (2.39 – 3.97 mg/L)

NOECReproduction

2.00 mg/L

LOECReproduction

4.00 mg/L

A summary of all test item related effects concerning the adult mortality and growth is given in Table 2. The assessed endpoints are based on the nominal concentrations of the test item and the active ingredient.

Table 2:           Test Item Related Effects on Adult Mortality (EC10, EC50 and EC100) and Growth

                         (based on the nominal concentrations of the test item and the active ingredient)

Effects

Sodium methyl oleyl taurate

Nominal concentrations of the test item [mg/L]

Control

0.500

0.305

1.00

0.610

2.00

1.22

4.00

2.44

8.00

4.88

Parental Daphnids: Mean Dry Weight [mg]

  1.21

  1.25

  1.20

  1.11

    0.87

---

Parental Daphnids: Mean Body Length [mm]

  5.23

  5.68

  5.18

  5.10

    5.58

---

Adult Mortality after 21 Days [%]

  0

  0

  0

  0

    0

1001)

EC10 Adult Mortality

4.00 mg/L EC10 Adult Mortality 8.00 mg/L

EC50 Adult Mortality

(with 95 % confidence limits)

5.66 mg/L (4.00 – 8.00 mg/L)

EC100 Adult Mortality

8.00 mg/L

SD        = standard deviation

1)           = significant adult mortality (> 20 %)

---         = not applicable, due to 100 % adult mortality

t

 

 

·          In order to prove the validity of the test system and test conditions at the test facility, an acute immobilisation test according to DIN 38412 L 11 is monthly carried out with potassium dichromate as reference item.
The EC50 of the reference item was
1.69 mg/L (95% confidence limits: 1.41 - 2.12 mg/L) after 24 hours and therefore within the prescribed concentration range of 1.0 - 2.5 mg/L of quality criteria according to AQS P 9/2 (05/1996) for daphnids clone 5 cultured in Elendt M4 medium. The EC50-value of the reference item is also within the recommended range of 0.6 - 2.1 mg/L according to OECD-Guideline 202.

Description of key information

The significant increase of the reproductive output at the concentration level of 4.00 mg/L was the most sensitive effect in this study. At the concentration level of 4.00 mg/L, an increased number of living juveniles, broods and an increased number of living juveniles per brood were observed.

Therefore, the No Observed Effect Concentration (NOEC) after 21 days was assessed at 2.00 mg/L and the Lowest Observed Effect Concentration (LOEC) was assessed at 4.00 mg/L. Based on the nominal concentrations of the active ingredient, the NOEC was 1.22 mg a.i./L and the LOEC was 2.44 mg a.i./L.

The EC10 for the increase of the reproductive output was calculated by sigmoidal dose-response regression to be 2.35 mg/L (95% confidence limits: 1.63 – 3.37 mg/L). The EC50 was calculated accordingly to be 3.40 mg/L (95 % confidence limits: 2.39 – 3.97 mg/L).

Based on the nominal concentrations of the active ingredient, the EC10 for the increase of the reproductive output was 1.43 mg a.i./L (95 % confidence limits: 0.994 – 2.06 mg a.i./L) and the EC50 was 2.07 mg/L (95 % confidence limits: 1.46 – 2.42 mg/L).

The EC50-value for the adult mortality was calculated to be 5.66 mg/L (95% confidence limits:  4.00 – 8.00 mg/L, which corresponds to 3.45 mg a.i./L (95% confidence limits: 2.44 – 4.88 mg a.i./L based on the nominal concentrations of the active ingredient. The EC100-value for the adult mortality was 8.00 mg/L, which corresponds to 4.88 mg a.i./L.

Endpoints assessed       Sodium methyl oleyl taurate

      Nominal concentration

of the test item

[mg/L]       Nominal concentration

of the active ingredient

[mg a.i./L]

EC10 Reproduction

(with 95 % confidence limits)       2.35 (1.63 – 3.37)       1.43 (0.994 – 2.06)

EC50 Reproduction

(with 95 % confidence limits)       3.40 (2.39 – 3.97)       2.07 (1.46 – 2.42)

EC10 Adult Mortality

(with 95 % confidence limits)       4.00 < EC10 Adult Mortality < 8.00       2.44 < EC10 Adult Mortality < 4.88

EC50 Adult Mortality

(with 95 % confidence limits)       5.66 (4.00 – 8.00)       3.45 (2.44 – 4.88)

EC100 Adult Mortality       8.00       4.88

NOECReproduction       2.00       1.22

LOECReproduction       4.00       2.44

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater invertebrates:
2 mg/L

Additional information